Removing the redundant ac-power switch

Use this topic when you need to remove a redundant ac-power switch.

Use the reference numbers in parentheses at the end of each notice, such as (C003) for example, to find the matching translated notice in IBM® Systems Safety Notices.

1. Turn off each SAN Volume Controller node that is connected by an uninterruptible power supply to the redundant ac-power switch. See MAP 5350: Powering off a SAN Volume Controller node.
   1. One or two nodes might be connected to the redundant ac-power switch. If two nodes are connected to the redundant ac-power switch, you must ensure that both nodes are not in the same I/O group before you turn off the nodes. If the nodes are both turned off and they are in the same I/O group, the customer will lose access to the data that is managed by that I/O group.
   2. If both nodes that are powered by the redundant ac-power switch are in the same I/O group, turn off one node, disconnect it from the redundant ac-power switch, and connect it to a different power source. Then turn the node back on. When it has recovered and rejoined the I/O group, it can maintain the I/O access when the other node is turned off and when the redundant ac-power switch is removed. If you have had to perform this operation, pay particular attention to checking when it is safe to turn off the second node. See MAP 5350: Powering off a SAN Volume Controller node.
2. Remove both the redundant ac-power switch input-power cables from the site power distribution unit and unthread them in the rack, so they will slide out when the redundant ac-power switch is removed. There might be enough access to disconnect them from the redundant ac-power switch while it is in the rack, but often it is more convenient to leave them attached and remove them with the redundant ac-power switch.
3. Remove the one or two redundant ac-power switches to 2145 UPS-1U power cables from the redundant ac-power switch. There is no need to disconnect them from the 2145 UPS-1U.
4. Remove the four screws that hold the redundant ac-power switch in the rack. Be careful to support the redundant ac-power switch during this procedure because the screws are the only support for the unit.
5. The redundant ac-power switch can be slid out of the rack along with the input-power cables if they are still attached.